Weird question about frequencies

Ninja_Harbinger · 13th July 2012, 9:14 AM

Hey guys,

I've been wondering for a while how speakers produce so many different frequencies at once. Any ideas?

Thanks,
Ninja!

Stooge007 · 13th July 2012, 11:04 AM

i didn't realise Google was down

http://www.thenakedscientists.com/HT...question/3077/

etc. etc.

Pugs · 13th July 2012, 11:19 AM

Quote:

Originally Posted by Stooge007

i didn't realise Google was down

http://www.thenakedscientists.com/HT...question/3077/

etc. etc.

same...

http://en.wikipedia.org/wiki/Loudspeaker

Red Spade · 16th July 2012, 6:26 PM

Imagine a woofer moving to reproduce a simple sine wave, let's say at 40 cycles per second ie 40 Hz. Now imagine it in slow motion so that you can see the cone moving, and we watch it take 10 seconds for one cycle. Now let's add another sine wave at 400 Hz. To reproduce the 40 Hz tone it moves much more, but the 400 Hz tones are much smaller strokes. So whilst we watch the cone move slowly for the 40 Hz, in that time we notice the smaller and more rapid travels where 10 cycles have happened for each one, in order to reproduce both tones at the same time. The fact that higher frequencies require much less excursion help us out greatly when it comes to reproducing so many frequencies all at the same time.

Now the 400 Hz tone is altered by the fact that the 40 Hz tone shifts its base position and this causes a form of distortion called intermodulation distortion.

Now there comes a point where the cone can no longer travel as a perfect piston, so it starts to become more complex in behaviour. Now we see cone bending at higher frequencies. This is seen as a breakdown of the ideal behaviour we want, we often see a sharp peak in response and also ripples in the impedance plot. You don't want to use a driver in this range.

13th July 2012, 11:04 AM	#2
Stooge007 Member Join Date: Aug 2006 Location: The Shire, Sydney Posts: 5,202	i didn't realise Google was down http://www.thenakedscientists.com/HT...question/3077/ etc. etc. __________________ Over 140 successful trades, most recent: ilmman, Nafe, PANZERAMD, robertgd, GotTone, JLOH, DanWA, Esposch, BevanMX5, SingAlong, ChaoS-GoD, someon3, ELiTEE, Elfanger, peteed1985, alexis, onbail, xsphera, OAG, Duff Man, skiitz, byson, Cestevenson, ShaunDXB, Piroteknik, myf360f1, Thraxeh, austin nguyen, QLDguy1, cooleagles, Temp16, Haillion, nordica-k2, Barra-oz, austin nguyen, MAXKNOTT, LG456, junkie13, Reveng3, sunjet, 2red, jbomb, OnGsTa, k1ll3r, DEMONDOCTOR, dabell, bumthology, Zee, JWM

16th July 2012, 6:26 PM	#4
Red Spade Member Join Date: Feb 2010 Location: Melbourne Posts: 73	Imagine a woofer moving to reproduce a simple sine wave, let's say at 40 cycles per second ie 40 Hz. Now imagine it in slow motion so that you can see the cone moving, and we watch it take 10 seconds for one cycle. Now let's add another sine wave at 400 Hz. To reproduce the 40 Hz tone it moves much more, but the 400 Hz tones are much smaller strokes. So whilst we watch the cone move slowly for the 40 Hz, in that time we notice the smaller and more rapid travels where 10 cycles have happened for each one, in order to reproduce both tones at the same time. The fact that higher frequencies require much less excursion help us out greatly when it comes to reproducing so many frequencies all at the same time. Now the 400 Hz tone is altered by the fact that the 40 Hz tone shifts its base position and this causes a form of distortion called intermodulation distortion. Now there comes a point where the cone can no longer travel as a perfect piston, so it starts to become more complex in behaviour. Now we see cone bending at higher frequencies. This is seen as a breakdown of the ideal behaviour we want, we often see a sharp peak in response and also ripples in the impedance plot. You don't want to use a driver in this range. __________________ Audio blog .::. DIY projects, articles and resources .::. Writer for Hifi Zine: http://www.hifizine.com/ DSP active point source horns + T20 sub horns under the floor + 8" waveguide surrounds + Custom Acoustic treatment